Hello, 

I'm due to replace my sparkplugs for my next service. I removed my original ones to see what type I needed and they are Ford HYFS 092YEC. I have done numerous searches and cannot find any with this serial number on, have they been replaced with another type. I was wanting to keep to oem ford but they don't seem to be available,  can anyone advise what type do I need as they vary in price and type so much. Ford Fiesta 1.0 ecoboost st line edition 2021 model.

I think it's extremely unlikely that you actually need to change them now on a 3 year old car. Leave them be. I don't know where you've got this schedule info from but if I consult the Haynes manual for my own car for instance, although it lists renewing spark plugs in the 'every 37500 miles or 3 years' category, which I found very suspect, if you read the section on actually replacing them it states "If the correct type is used and the engine is in good condition, the spark plugs should not need attention between scheduled intervals". It would have been better if it had actually said 'check and replace if necessary' in the schedule. It's exactly the same in a newer Fiesta Haynes manual I have. My own spark plugs haven't been changed since, I dunno, 2010 maybe, and when I checked them a year or so ago they were still okay.

You should learn how to actually inspect the condition of the spark plugs to determine whether or not replacement is necessary.

Sticking to Ford brand spark plugs is a bit silly, just go with a good well known name brand like NGK, it won't make any difference. The Ford brand ones are just going to be rebadged from one of these well known brands anyway. One decision for you to make if you want to splash out some cash is whether to get an ordinary type or something more special like Iridium ones. Some vehicle manuals may actually specify that you should use Iridum ones as standard. Check your manual.

You may also want to get ones that require the same socket size if you have a special spark-plug socket, and you'd need to ensure that the dimensions of the threaded section that screw into the engine are the same, but you can just trust the compatibility features of sites like eurocarparts for that and then just double check by comparing one with an old one before fitting.

Serial numbers are unique btw, you won't find anything with the same serial number. Part number is what you're thinking of.

Hi rd 457, thanks for the reply. Yes I thought that was the part number not a serial number, my mistake.I was going off the next ford scheduled service for my vehicle which states that new sparkplugs would be installed. This was found on the fordapp, although my car has only done 27000 I wouldn't of thought they would of needed changing. I was just trying to keep to the ford spec. I think I will take your advice and go with NGK or Bocsh. On my older cars in the past I just went with whatever euro parts give me. Thanks again.